[1] [1] Chen M Y, Zhang Y K. Bend insensitive design of large-mode-area microstructured optical fibers［J］. Journal of Lightwave Technology, 2011, 29(15): 2216-2222.

[2] [2] Kong F, Dunn C, Parsons J, et al. Large-mode-area fibers operating near single-mode regime［J］. Optics Express, 2016, 24(10): 10295-10301.

[3] [3] Knight J C, Birks T A, Russell P St J, et al. All-silica single-mode optical fiber with photonic crystal cladding［J］. Optics Letters, 1996, 21(19): 1547-1549.

[4] [4] Schmidt O, Rothhardt J, Eidam T, et al. Single-polarization large-mode-area Yb-doped photonic crystal fiber［C］. Conference on Lasers and Electro-Optics, Optical Society of America, 2008: CMB2.

[5] [5] Geng Pengcheng, Hou Lantian, Han Weitao, et al. Design of large mode area Yb3+-doped seven-core photonic crystal fiber［J］. Acta Optica Sinica, 2010, 30(9): 2719-2723.

[6] [6] Wang Ziwei, Wang Zhaokun, Zou Feng, et al. High-pear-power rod-type photonic crystal fiber amplifier for picosecond pulse［J］. Chinese J Lasers, 2016, 43(10): 1001001.

[7] [7] Xiang P, Liang D. Fundamental-mode operation in polarization-maintaining ytterbium-doped fiber with an effective area of 1400 μm2［J］. Optics Letters, 2007, 32(4): 358-360.

[8] [8] Vogel M M, Abdou-Ahmed M, Voss A, et al. Very-large-mode-area, single-mode multicore fiber［J］. Optics Letters, 2009, 34(18): 2876-2878.

[9] [9] Chen M Y, Sun B, Zhang Y K, et al. Design of all-solid large-mode area microstructured-core optical fibers［J］. Optics Communications, 2010, 283(16): 3153-3157.

[10] [10] Ren Guobin, Wang Zhi, Lou Shuqin, et al. Study on photonic crystal fiber by effective-index model［J］. Chinese J Lasers, 2004, 31(6): 723-727.

[11] [11] Birks T A, Knight J C, Russell P S J, et al. Endlessly single-mode photonic crystal fiber［J］. Optics Letters, 1997, 22(13): 961-963.

[12] [12] Chow D M, Sandoghchi S R, Adikan F R M. Fabrication of photonic crystal fibers［C］. IEEE 3rd International Conference on Photonics, 2012: 13175947.

[13] [13] Agrawal G P. Nonlinear fiber optics［M］. Jia Dongfang, Transl. 3rd ed. Beijing: Publishing House of Electronics Industry, 2002: 7.

[14] [14] Liao Suying. Study on the characteristics of laser mode field in large-mode-area Yb3+ doped fibers［D］. Beijing: Tsinghua University, 2009: 42-43.

[15] [15] NKT company. Modal properties of Aerogain-rod high power ytterbium rod fiber gain modules［EB/OL］. http://www.nktphotonics.com/lasers-fibers/en/product/aerogain-rod-high-power-ytterbium-rod-fiber-gain-modules/.